1. Field of the Invention
The present invention is related to a safety lock with a switching unit for a computer, and especially to a safety lock for a computer of which the switching unit is provided in the safety lock to control operation of a lock head.
2. Description of the Prior Art
In a prior patent case, namely the U.S. Pat. No. 3,136,017 titled (fastening device), a lock head with a T shaped rotating axle is provided, and a fixing seat is provided allowing extending through of a T shaped rotating shank, a protruding seat is provided in front of the fixing seat for engaging in a rectangular lock hole provided on a wall of an article to be locked; and by rotating of the T shaped rotating axle, when a transverse head on the tailing end of the T shaped rotating axle is aligned with and parallel to the protruding seat, an unlocking position is formed, while a locking position is formed if they perpendicularly cross over each other.
Moreover, in prior patent cases including a U.S. Pat. No. 5, 381,685 titled (computer physical security device) and a U.S. Pat. No. 5,327,752 titled (computer equipment lock), the above stated lock head structure is used to provide safety locking devices for computers having rectangular lock holes in order to prevent the computers from stealing.
In the prior patent cases concerning safety locks for computers, by virtue that a transverse head on the tailing end of a T shaped rotating axle is extended into a wall of a computer having a lock hole, and is not visible for an operator who can not thereby assure whether the lock head is at a locking position or an unlocking position; thereby it is very hard to make sure whether the lock head can be drawn out from the lock hole of the computer. If the lock head is forcedly drawn out in a locking state, the lock hole may be destroyed to damage the commodity computer; contrarily, if the lock hole is deemed as being locked when it is in an unlocking position, stealing will not at all be prevented. And these are the main defects of the conventional techniques.